JP7737111B2 - Abnormality location determination device, abnormality location determination method, and program - Google Patents

Description

The present invention relates to an abnormality location determination device, an abnormality location determination method, and a program.

An OTDR (Optical Time Domain Reflectometer) is typically used to detect abnormalities in the transmission path of an optical fiber communication system. An OTDR is a measuring instrument that can evaluate optical fiber loss by observing the reflected light (backscattered light) of optical pulses sent down the optical fiber. OTDRs are used in testing during optical fiber installation and maintenance work, as well as on active transmission paths where data is actually being transmitted. An OTDR can represent the loss level as a waveform relative to the distance from the optical pulse's incident point. Using an OTDR, it is possible to detect abnormalities such as optical fiber breaks, or abnormalities causing loss such as connector connection loss, based on the point where waveform disturbances occur and the shape of the waveform.

Meanwhile, attempts are also underway to detect abnormalities that occur in the transmission paths of optical fiber communication systems using the optical signals themselves that are actually used in data communications. For example, the technology described in Non-Patent Document 1 uses a constellation, in which the digitally modulated signal obtained at the receiver of a digital coherent optical transceiver is represented as a two-dimensional image of real and imaginary axes, as a learning parameter in machine learning. The technology described in Non-Patent Document 1 then uses a trained neural network to identify whether the optical fiber is bent or not based on distortion in the constellation.

For example, when identifying whether an optical fiber is bent, different labels are assigned to the constellations when the optical fiber is not bent and the constellations when it is bent. These constellations are input into a neural network, which then learns the regularity of the constellation shape for each label. When an unknown, unlabeled constellation is input to the trained neural network, the neural network outputs the most appropriate label based on past regularity. For example, changes in the constellation shape caused by bending an optical fiber are so small that they cannot be distinguished by human vision, but with the use of machine learning techniques such as neural networks, they can now be detected.

In addition, optical transceivers generally have the ability to measure, for example, the received power and bit error rate in order to detect degradation in the quality of received signals. In the operation and maintenance of optical networks, it is desirable to not only use the machine learning-based anomaly detection method described above, but also to utilize technologies already built into optical transceivers to quickly detect anomalies that could be a precursor to a communication outage and identify the location of the anomaly before it actually occurs.

T. Tanaka, S. Kuwabara, H. Nishizawa, T. Inui, S. Kobayashi and A. Hirano, “Field Demonstration of Real-time Optical Network Diagnosis Using Deep Neural Network and Telemetry”, Optical Fiber Communications Conference and Exhibition (OFC) 2019, Tu2E.5., February, 2019

As mentioned above, OTDRs are capable of estimating with greater accuracy the location of abnormalities in the transmission path of an optical fiber communication system. However, because OTDRs use a light source that is different from the optical transceiver they measure, it is difficult to detect abnormalities occurring in the optical transceiver itself, such as laser malfunctions. Furthermore, OTDRs are measurement devices dedicated to abnormality detection and are introduced as an add-on to optical fiber communication systems. OTDRs are also more expensive than optical transceivers. As such, in terms of functionality and cost, OTDRs are not suitable for comprehensively detecting abnormalities occurring at all points in an optical network.

On the other hand, a detection means that detects abnormalities in the transmission path of an optical fiber communication system by using the signal quality measurement function already installed in the optical transceiver can detect abnormalities in the optical transceiver itself. This detection means is also more economical because it does not require a dedicated measurement device for abnormality detection, such as an OTDR. However, this detection means has the problem that when an abnormality, such as a deterioration in signal quality, occurs, it is difficult to determine which section of the transmission path the abnormality is occurring in.

The present invention was made in consideration of the above points, and aims to provide an abnormality location determination device, an abnormality location determination method, and a program that can determine the location of an abnormality in the transmission path of an optical fiber communication system using the signal quality measurement function provided by an optical transceiver.

One aspect of the present invention is an anomaly location determination device that includes a collection unit that collects transmission signal information for a transmission section obtained by optical transceivers from multiple optical nodes that make up an optical network; a diagnosis unit that diagnoses the normality of the transmission section based on the transmission signal information; and a determination unit that determines an anomaly location in the optical network based on the results of multiple diagnoses by the diagnosis unit.

Another aspect of the present invention is a method for determining the location of an abnormality, comprising: a collection step of collecting transmission signal information for a transmission section obtained by optical transceivers from multiple optical nodes constituting an optical network; a diagnosis step of diagnosing the normality of the transmission section based on the transmission signal information; and an estimation step of estimating the location of an abnormality in the optical network based on multiple diagnostic results obtained in the diagnosis step.

Another aspect of the present invention is a program for causing a computer to function as the above-mentioned abnormality location determination device.

This invention makes it possible to determine the location of an abnormality in the transmission path of an optical fiber communication system using the signal quality measurement function provided by the optical transceiver.

1 is a diagram illustrating an overall configuration of an optical network system 1 according to a first embodiment of the present invention. 4 is a flowchart showing an operation of the optical network state estimating device 20 in the first embodiment of the present invention. FIG. 2 is a diagram illustrating an example of the configuration of an optical network for explaining the operation of an optical network state estimation device 20. 10 is a diagram showing an example of a correspondence between a pattern of abnormality occurrence locations and an optical transceiver in which an abnormality is detected by a signal state diagnostic unit 22. FIG. FIG. 1 is an overall configuration diagram of an optical network system 1b according to a first modified example of the first embodiment of the present invention. FIG. 10 is an overall configuration diagram of an optical network system 1c according to a second modified example of the first embodiment of the present invention. FIG. 10 is a cross-sectional view of a multi-core optical fiber 30c of an optical network system 1c according to a second modification of the first embodiment of the present invention. 10 is a flowchart showing the operation of an optical network state estimating device 20d according to the second embodiment of the present invention. FIG. 2 is a diagram illustrating an example of the configuration of an optical network for explaining the operation of the optical network state estimation device 20d. 10 is a diagram showing an example of a correspondence between a pattern of abnormality occurrence locations and an optical transceiver in which an abnormality is detected by a signal state diagnostic unit 22. FIG. 10 is a flowchart showing the operation of the optical network state estimating device according to a modified example of the second embodiment of the present invention.

First Embodiment
A first embodiment of the present invention will be described below with reference to the drawings.

[Configuration of optical network system]
The configuration of the optical network system according to this embodiment will be described below. Fig. 1 is an overall configuration diagram of an optical network system 1 according to a first embodiment of the present invention. The optical network system 1 is an optical fiber communication system. As shown in Fig. 1, the optical network system 1 according to this embodiment is configured to include four optical node devices 10 and an optical network state estimation device 20. Note that in this embodiment, as an example, the number of optical node devices 10 included in the optical network system 1 is four, but this is not limited to this and any number may be used.

Four optical node devices 10 are communicatively connected to each other via optical links using optical fibers, forming an optical network. As shown in Figure 1, each optical node device 10 comprises an optical signal input/output unit 11 and an optical cross-connect unit 12.

The optical signal input/output unit 11 inputs and outputs signals transmitted over the optical link connecting the optical node devices 10. The optical signal input/output unit 11 is equipped with optical transceivers 110 (Tx/Rx (Transmitter/Receiver)) that transmit client signals, depending on the actual communication situation. Transmission signal information for the transmission section acquired by the optical transceiver 110 is sent to the optical network state estimation device 20. The transmission signal information includes information related to optical communications that is necessary to estimate the state of the signal transmitted over the optical link. For example, the transmission signal information includes the digitally modulated signal received by the optical transceiver 110, the received power value, and the bit error rate value.

The optical cross-connect unit 12 determines the input and output paths of optical signals.

The optical network state estimation device 20 evaluates the communication state of an optical network composed of four optical node devices 10. As shown in FIG. 1, the optical network state estimation device 20 includes a transmission signal information collection unit 21, a signal state diagnosis unit 22, and an abnormality location estimation unit 23.

The transmission signal information collection unit 21 receives transmission signal information from each optical node device 10 in the monitored section of the optical network. The transmission signal information collection unit 21 outputs the received transmission signal information to the signal status diagnosis unit 22.

The signal state diagnostic unit 22 acquires the transmission signal information output from the transmission signal information collection unit 21. The signal state diagnostic unit 22 diagnoses the normality of the transmission section based on the acquired transmission signal information. Note that diagnosing normality here means detecting the presence or absence of an abnormality. Specifically, the signal state diagnostic unit 22 determines whether the transmission section through which each optical transceiver 110 passes (is used) is normal (whether an abnormality has occurred). For example, the signal state diagnostic unit 22 determines that an abnormality has occurred in the transmission section when the received power value or bit error rate value falls below a predetermined threshold. The signal state diagnostic unit 22 outputs information indicating the diagnosis result of the normality of the transmission section (the abnormality detection result) to the abnormality location estimation unit 23.

The signal condition diagnosis unit 22 may be configured to perform machine learning using a neural network or the like using, for example, a digitally modulated signal, and then use the trained neural network or the like to determine whether or not an abnormality has occurred in the transmission section.

The abnormality location estimation unit 23 acquires information indicating the diagnosis results of the normality of the transmission section, output from the signal status diagnosis unit 22. Based on the acquired information indicating the diagnosis results, the abnormality location estimation unit 23 estimates the location where the abnormality has occurred in the optical network (hereinafter referred to as the "abnormality location"). Note that the abnormality location in this embodiment refers to the optical link where the abnormality has occurred and the optical transceiver 110 where the abnormality has occurred.

[Operation of Optical Network State Estimation Device]
2 to 4, an example of the operation of the optical network state estimation device 20 will be described. Note that in this embodiment, the configuration of the optical network, the connection status of each optical transceiver 110, and the diagnosis result of the signal state diagnosis unit 22 on the normality of each optical transceiver 110 are assumed to be known.

In this embodiment, for ease of explanation, it is assumed that an abnormality occurs in one location in the optical network, and that abnormalities do not occur in multiple locations at the same time. Specifically, in this embodiment, it is assumed that an abnormality occurs in one of the optical links or one of the optical transceivers 110 in the optical network.

Figure 2 is a flowchart showing the operation of the optical network state estimation device 20 in the first embodiment of the present invention. Figure 3 is a diagram showing an example of the configuration of an optical network to explain the operation of the optical network state estimation device 20. Figure 4 is a diagram showing the pattern of abnormality occurrences and the results of normality diagnosis in the optical network shown in Figure 3.

The operation of the optical network state estimation device 20 shown in the flowchart of Figure 2 is initiated, for example, when the signal state diagnosis unit 22 diagnoses that at least one of the optical transceivers 110 is abnormal.

First, the abnormality location estimation unit 23 of the optical network state estimation device 20 determines, for each optical link in the optical network being evaluated, whether all optical transceivers 110 using the optical link have been diagnosed as abnormal (step S001).

If all optical transceivers 110 using the optical link are diagnosed as abnormal (step S001, YES), the abnormality location estimation unit 23 performs a process to set an abnormality occurrence flag for that optical link (step S002). The abnormality location estimation unit 23 repeats the above process for all optical links in the optical network being evaluated, and then proceeds to the next step.

Next, for each optical transceiver 110 diagnosed as abnormal by the signal condition diagnosis unit 22, the abnormality occurrence location estimation unit 23 determines whether an abnormality occurrence flag has been set (by the processing of step S002 above) in all optical links through which the optical transceiver 110 passes (step S003). In other words, the abnormality occurrence location estimation unit 23 determines whether an abnormality occurrence flag has been set (by the processing of step S002 above) in at least one optical link through which the optical transceiver 110 passes.

If an abnormality occurrence flag has not been set for all optical links through which the optical transceiver 110 passes (step S003: YES), the abnormality occurrence location estimation unit 23 performs a process to set an abnormality occurrence flag for the optical transceiver 110 in question (step S005).

On the other hand, if an abnormality occurrence flag has been set (by the processing of step S002 above) for at least one optical link through which the optical transceiver 110 passes (step S003: NO), the abnormality occurrence location estimation unit 23 determines whether or not there is an optical link among the optical links for which an abnormality occurrence flag has been set that is being used only by the optical transceiver 110 (and is not being used by other optical transceivers 110) (step S004).

If there is an optical link among the optical links for which an abnormality occurrence flag is set that is used only by the optical transceiver 110 (and not used by other optical transceivers 110) (step S004, YES), the abnormality occurrence location estimation unit 23 performs a process of setting an abnormality occurrence flag for that optical transceiver 110 (step S005).

When the abnormality location estimation unit 23 has repeated the processing from step S003 onwards for all optical transceivers 110 diagnosed as abnormal by the signal state diagnosis unit 22, the operation of the optical network state estimation device 20 shown in the flowchart of Figure 2 ends.

Below, we will explain a specific example of when the processing of the flowchart shown in Figure 2 above is performed, with reference to Figures 3 and 4.

Figure 3 shows the overall configuration of the optical network system 1a and the configuration of the optical network in the specific example described below. As shown in Figure 3, the optical network system 1a in the specific example described below is configured to include optical node devices 10A, 10B, 10C, 10D, and an optical network state estimation device 20.

Optical node device 10A, optical node device 10B, optical node device 10C, and optical node device 10D are communicatively connected to one another via optical links using single-mode optical fibers 30, forming an optical network. Optical node device 10A, optical node device 10B, optical node device 10C, and optical node device 10D each include an optical signal input/output unit 11 and an optical cross-connect unit 12. Furthermore, optical cross-connect unit 12 includes a wavelength multiplexing unit 15.

Hereinafter, the optical link connecting optical node device 10A and optical node device 10B will be referred to as "optical link A-B," the optical link connecting optical node device 10B and optical node device 10C will be referred to as "optical link B-C," and the optical link connecting optical node device 10C and optical node device 10D will be referred to as "optical link C-D."

The optical signal input/output unit 11 is equipped with optical transceivers (Tx/Rx) that transmit client signals depending on the actual communication situation. In the specific example described below, as shown in FIG. 3, it is assumed that optical transceiver 110-1 is provided between optical node device 10A and optical node device 10C, optical transceiver 110-2 is provided between optical node device 10A and optical node device 10B, and optical transceiver 110-3 is provided between optical node device 10B and optical node device 10D.

As shown in FIG. 3, the optical links that optical transceiver 110-1 passes through are optical link A-B and optical link B-C, the optical link that optical transceiver 110-2 passes through is only optical link A-B, and the optical links that optical transceiver 110-3 passes through are optical link B-C and optical link C-D. With the above configuration, wavelength-multiplexed communications are performed by optical transceivers 110-1, 110-2, and 110-3 between optical node device 10A and optical node device 10C, between optical node device 10A and optical node device 10B, and between optical node device 10B and optical node device 10D, respectively.

The optical network state estimation device 20 evaluates the communication state of an optical network composed of optical node devices 10A, 10B, 10C, and 10D. As shown in FIG. 3, the optical network state estimation device 20 includes a transmission signal information collection unit 21, a signal state diagnosis unit 22, and an abnormality location estimation unit 23.

As mentioned above, in this embodiment, when an abnormality occurs in the optical network, it is assumed that the abnormality occurs in one location and that abnormalities do not occur in multiple locations at the same time. Therefore, in this specific example, the location where the abnormality occurs in the optical network is either one of optical link A-B, optical link B-C, or optical link C-D, or one of optical transceiver 110-1, optical transceiver 110-2, or optical transceiver 110-3. In other words, there are six possible locations where an abnormality can occur in the optical network of this specific example.

Note that abnormalities occurring in optical links A-B, B-C, and C-D are, for example, communication failures caused by bending of the optical fiber. Furthermore, abnormalities occurring in optical transceivers 110-1, 110-2, and 110-3 are, for example, malfunctions in the optical transceivers themselves.

Figure 4 shows six possible patterns of abnormality locations that can occur in the optical network of Figure 3, and the correspondence between these and the optical transceivers in which the signal status diagnosis unit 22 will detect an abnormality if an abnormality occurs at each abnormality location.

As shown in Figure 4, if the abnormality occurs in optical link A-B, the abnormality is detected in optical transceivers 110-1 and 110-2, which are optical transceivers (Tx/Rx) passing through optical link A-B. If the abnormality occurs in optical link B-C, the abnormality is detected in optical transceivers 110-1 and 110-3, which are optical transceivers passing through optical link B-C. If the abnormality occurs in optical link C-D, the abnormality is detected in optical transceiver 110-3, which is an optical transceiver passing through optical link C-D.

Furthermore, as shown in FIG. 4, if the abnormality occurs in optical transceiver 110-1, the abnormality is detected in optical transceiver 110-1; if the abnormality occurs in optical transceiver 110-2, the abnormality is detected in optical transceiver 110-2; and if the abnormality occurs in optical transceiver 110-3, the abnormality is detected in optical transceiver 110-3. Based on the correspondence between the abnormality occurrence locations and the optical transceivers in which the abnormality is detected, it is possible to narrow down or identify the abnormality location from the optical transceiver in which the abnormality is detected.

[Example of setting an error flag]
Hereinafter, a flow up to the setting of an abnormality occurrence flag by the operation of the optical network state estimating device 20 shown in FIG. 2 will be described for each of six patterns of abnormality occurrence locations that can occur in the optical network of FIG.

First, consider the first case, where an abnormality occurs in optical link A-B due to, for example, bending of the optical fiber. In this case, as described above, an abnormality is detected in optical transceiver 110-1 and optical transceiver 110-2. The abnormality location estimation unit 23 of the optical network state estimation device 20 determines whether all optical transceivers using the optical links A-B, B-C, and C-D have been diagnosed as abnormal (step S001 in Figure 2).

As shown in Figure 3, the optical transceivers using optical link A-B are optical transceiver 110-1 and optical transceiver 110-2. As mentioned above, both optical transceiver 110-1 and optical transceiver 110-2 have been diagnosed as abnormal (step S001 in Figure 2: YES), so the abnormality location estimation unit 23 sets an abnormality flag for optical link A-B (step S002 in Figure 2).

Also, as shown in Figure 3, the optical transceivers using optical link B-C are optical transceiver 110-1 and optical transceiver 110-3. As mentioned above, optical transceiver 110-1 has been diagnosed as abnormal, but optical transceiver 110-3 has not been diagnosed as abnormal (step S001: NO in Figure 2), so the abnormality location estimation unit 23 does not set an abnormality occurrence flag for optical link B-C.

Also, as shown in Figure 3, the optical transceiver using optical link C-D is optical transceiver 110-3. Because optical transceiver 110-3 has not been diagnosed as abnormal (step S001: NO in Figure 2), the abnormality location estimation unit 23 does not set an abnormality occurrence flag for optical link C-D.

Next, for each of the optical transceivers 110-1 and 110-2 diagnosed as abnormal by the signal condition diagnosis unit 22, the abnormality location estimation unit 23 determines whether an abnormality flag has been set for all optical links through which the optical transceiver passes (step S003 in Figure 2).

As shown in FIG. 3, the optical links through which the optical transceiver 110-1 passes are optical link A-B and optical link B-C. As mentioned above, the abnormality flag is not set for optical link B-C, but the abnormality flag is set for optical link A-B. Therefore, among the optical links through which the optical transceiver 110-1 passes, there is an optical link for which the abnormality flag is set (i.e., optical link A-B). In this case (step S003 in FIG. 2: NO), the abnormality location estimation unit 23 determines whether the optical link A-B for which the abnormality flag is set is an optical link used only by the optical transceiver 110-1 (and not used by other optical transceivers) (step S004 in FIG. 2).

Since optical link A-B is used not only by optical transceiver 110-1 but also by optical transceiver 110-2 (step S004: NO in Figure 2), the abnormality location estimation unit 23 does not set an abnormality occurrence flag for optical transceiver 110-1.

As shown in FIG. 3, the only optical link through which the optical transceiver 110-2 passes is optical link A-B. As mentioned above, an abnormality occurrence flag is set on optical link A-B. Therefore, among the optical links through which the optical transceiver 110-2 passes, there is an optical link (i.e., optical link A-B) for which an abnormality occurrence flag is set. In this case (step S003 in FIG. 2: NO), the abnormality occurrence location estimation unit 23 determines whether the optical link A-B for which the abnormality occurrence flag is set is an optical link used only by the optical transceiver 110-2 (and not used by other optical transceivers) (step S004 in FIG. 2).

Since optical link A-B is used not only by optical transceiver 110-2 but also by optical transceiver 110-1 (step S004 in Figure 2: NO), the anomaly occurrence location estimation unit 23 does not set an anomaly occurrence flag for optical transceiver 110-2.

Therefore, in the network configuration shown in Figure 3, in a pattern in which an abnormality occurs in optical link A-B, an abnormality occurrence flag is set only for optical link A-B. In other words, if an abnormality occurs in optical link A-B, the abnormality occurrence location estimation unit 23 can correctly estimate that an abnormality has occurred in optical link A-B.

Figure 4 shows six possible patterns of abnormality locations that can occur in the optical network of Figure 3, and the correspondence between these and the abnormality flags that are set when an abnormality occurs at each abnormality location.

Next, consider the second case, where an abnormality occurs in optical link B-C due to, for example, bending of the optical fiber. In this case, as described above, abnormalities are detected in optical transceiver 110-1 and optical transceiver 110-3. The abnormality location estimation unit 23 of the optical network state estimation device 20 determines whether all optical transceivers using the optical links A-B, B-C, and C-D have been diagnosed as abnormal (step S001 in Figure 2).

As shown in Figure 3, the optical transceivers using optical link A-B are optical transceiver 110-1 and optical transceiver 110-2. As mentioned above, optical transceiver 110-1 has been diagnosed as abnormal, but optical transceiver 110-2 has not been diagnosed as abnormal (step S001 in Figure 2: NO), so the abnormality location estimation unit 23 does not set an abnormality flag for optical link A-B.

Also, as shown in Figure 3, the optical transceivers using optical link B-C are optical transceiver 110-1 and optical transceiver 110-3. As mentioned above, both optical transceiver 110-1 and optical transceiver 110-3 have been diagnosed as abnormal (step S001 in Figure 2: YES), so the abnormality location estimation unit 23 sets an abnormality occurrence flag for optical link B-C (step S002 in Figure 2).

Furthermore, as shown in FIG. 3, the only optical transceiver using optical link C-D is optical transceiver 110-3. Because optical transceiver 110-3 has been diagnosed as abnormal (step S001: YES in FIG. 2), the abnormality occurrence location estimation unit 23 would normally set an abnormality occurrence flag for optical link C-D. However, if an abnormality occurs in optical link C-D, this would contradict the fact that optical transceiver 110-1, which does not use optical link C-D, has been diagnosed as abnormal (as described above) (because it is assumed that abnormalities do not occur at multiple locations simultaneously). Therefore, the abnormality occurrence location estimation unit 23 does not set an abnormality occurrence flag for optical link C-D.

Next, for each of the optical transceivers 110-1 and 110-3 diagnosed as abnormal by the signal status diagnosis unit 22, the abnormality location estimation unit 23 determines whether an abnormality occurrence flag has been set for all optical links through which the optical transceiver passes (step S003 in Figure 2).

As shown in FIG. 3, the optical links through which the optical transceiver 110-1 passes are optical link A-B and optical link B-C. As mentioned above, the abnormality flag is not set for optical link A-B, but the abnormality flag is set for optical link B-C. Therefore, among the optical links through which the optical transceiver 110-1 passes, there is an optical link for which the abnormality flag is set (i.e., optical link B-C). In this case (step S003 in FIG. 2: NO), the abnormality location estimation unit 23 determines whether the optical link B-C for which the abnormality flag is set is an optical link used only by the optical transceiver 110-1 (and not used by other optical transceivers) (step S004 in FIG. 2).

Since optical link A-B is used not only by optical transceiver 110-1 but also by optical transceiver 110-2 (step S004: NO in Figure 2), the abnormality location estimation unit 23 does not set an abnormality occurrence flag for optical transceiver 110-1.

As shown in FIG. 3, the optical links through which the optical transceiver 110-3 passes are optical link B-C and optical link C-D. As mentioned above, the abnormality flag is not set for optical link C-D, but the abnormality flag is set for optical link B-C. Therefore, among the optical links through which the optical transceiver 110-3 passes, there is an optical link for which the abnormality flag is set (i.e., optical link B-C). In this case (step S003 in FIG. 2: NO), the abnormality location estimation unit 23 determines whether the optical link B-C for which the abnormality flag is set is an optical link used only by the optical transceiver 110-3 (and not used by other optical transceivers) (step S004 in FIG. 2).

Since optical link B-C is used not only by optical transceiver 110-3 but also by optical transceiver 110-1 (step S004: NO in Figure 2), the anomaly occurrence location estimation unit 23 does not set an anomaly occurrence flag for optical transceiver 110-3.

Therefore, in the network configuration shown in Figure 3, in a pattern in which an abnormality occurs in optical link B-C, an abnormality occurrence flag is set only for optical link B-C. In other words, if an abnormality occurs in optical link B-C, the abnormality occurrence location estimation unit 23 can correctly estimate that an abnormality has occurred in optical link B-C.

Next, consider the third case, where an abnormality occurs in optical link C-D due to, for example, bending of the optical fiber. In this case, as described above, an abnormality is detected in optical transceiver 110-3. The abnormality location estimation unit 23 of the optical network state estimation device 20 determines whether all optical transceivers using the optical links A-B, B-C, and C-D have been diagnosed as abnormal (step S001 in Figure 2).

As shown in Figure 3, the optical transceivers using optical link A-B are optical transceiver 110-1 and optical transceiver 110-2. As mentioned above, neither optical transceiver 110-1 nor optical transceiver 110-2 has been diagnosed as abnormal (step S001: NO in Figure 2), so the abnormality location estimation unit 23 does not set an abnormality occurrence flag for optical link A-B.

Also, as shown in Figure 3, the optical transceivers using optical link B-C are optical transceiver 110-1 and optical transceiver 110-3. As mentioned above, optical transceiver 110-3 has been diagnosed as abnormal, but optical transceiver 110-1 has not been diagnosed as abnormal (step S001: NO in Figure 2), so the abnormality location estimation unit 23 does not set an abnormality occurrence flag for optical link B-C.

Also, as shown in Figure 3, the only optical transceiver using optical link C-D is optical transceiver 110-3. Because optical transceiver 110-3 has been diagnosed as abnormal (step S001 in Figure 2: YES), the abnormality location estimation unit 23 sets an abnormality occurrence flag for optical link C-D (step S002 in Figure 2).

Next, the abnormality location estimation unit 23 determines whether an abnormality occurrence flag has been set for all optical links through which the optical transceiver 110-3, which has been diagnosed as abnormal by the signal status diagnosis unit 22, passes (step S003 in Figure 2).

As shown in FIG. 3, the optical links through which the optical transceiver 110-3 passes are optical link B-C and optical link C-D. As mentioned above, the abnormality flag is not set for optical link B-C, but the abnormality flag is set for optical link C-D. Therefore, among the optical links through which the optical transceiver 110-3 passes, there is an optical link for which the abnormality flag is set (i.e., optical link C-D). In this case (step S003 in FIG. 2: NO), the abnormality location estimation unit 23 determines whether the optical link C-D for which the abnormality flag is set is an optical link used only by the optical transceiver 110-3 (and not used by other optical transceivers) (step S004 in FIG. 2).

Since optical link C-D is being used only by optical transceiver 110-3 (step S004 in Figure 2, YES), the anomaly occurrence location estimation unit 23 sets an anomaly occurrence flag for optical transceiver 110-3 (step S005 in Figure 2).

Therefore, in the network configuration shown in FIG. 3, in a pattern in which an abnormality occurs in optical link C-D, an abnormality occurrence flag is set for optical link C-D and optical transceiver 110-3. In other words, if an abnormality occurs in optical link C-D, the abnormality occurrence location estimation unit 23 cannot uniquely estimate the location of the abnormality, but it can narrow down the location of the abnormality by assuming that an abnormality has occurred in either optical link C-D or optical transceiver 110-3.

Next, consider the fourth pattern, where an abnormality occurs in optical transceiver 110-1, for example. In this case, as described above, an abnormality is detected only in optical transceiver 110-1. The abnormality location estimation unit 23 of the optical network state estimation device 20 determines whether all optical transceivers using the optical links A-B, B-C, and C-D have been diagnosed as abnormal (step S001 in Figure 2).

As shown in Figure 3, the optical transceivers using optical link A-B are optical transceiver 110-1 and optical transceiver 110-2. As mentioned above, optical transceiver 110-1 has been diagnosed as abnormal, but optical transceiver 110-2 has not been diagnosed as abnormal (step S001 in Figure 2: NO), so the abnormality location estimation unit 23 does not set an abnormality occurrence flag for optical link A-B.

Furthermore, as shown in FIG. 3, the optical transceivers using optical link B-C are optical transceiver 110-1 and optical transceiver 110-3. As mentioned above, optical transceiver 110-1 has been diagnosed as abnormal, but optical transceiver 110-3 has not been diagnosed as abnormal (step S001: NO in FIG. 2), so the abnormality location estimation unit 23 does not set an abnormality occurrence flag for optical link B-C.

Also, as shown in Figure 3, the optical transceiver using optical link C-D is optical transceiver 110-3. Because optical transceiver 110-3 has not been diagnosed as abnormal (step S001: NO in Figure 2), the abnormality location estimation unit 23 does not set an abnormality occurrence flag for optical link C-D.

Next, the abnormality location estimation unit 23 determines whether an abnormality occurrence flag has been set for all optical links through which the optical transceiver 110-1 diagnosed as abnormal by the signal status diagnosis unit 22 passes (step S003 in Figure 2).

As shown in FIG. 3, the optical links through which optical transceiver 110-1 passes are optical link A-B and optical link B-C. As mentioned above, no abnormality flags have been set for optical link A-B or optical link B-C. In this case (step S003 in FIG. 2: YES), the abnormality location estimation unit 23 sets an abnormality flag for optical transceiver 110-1 (step S005 in FIG. 2).

Therefore, in the network configuration shown in FIG. 3, in a pattern in which an abnormality occurs in optical transceiver 110-1, an abnormality occurrence flag is set only for optical transceiver 110-1. In other words, if an abnormality occurs in optical transceiver 110-1, the abnormality occurrence location estimation unit 23 can correctly estimate that the abnormality has occurred in optical transceiver 110-1.

Next, consider the fifth pattern, where an abnormality occurs in optical transceiver 110-2, for example. In this case, as described above, an abnormality is detected only in optical transceiver 110-2. The abnormality location estimation unit 23 of the optical network state estimation device 20 determines whether all optical transceivers using the optical links A-B, B-C, and C-D have been diagnosed as abnormal (step S001 in Figure 2).

As shown in Figure 3, the optical transceivers using optical link A-B are optical transceiver 110-1 and optical transceiver 110-2. As mentioned above, optical transceiver 110-2 has been diagnosed as abnormal, but optical transceiver 110-1 has not been diagnosed as abnormal (step S001: NO in Figure 2), so the abnormality location estimation unit 23 does not set an abnormality occurrence flag for optical link A-B.

Furthermore, as shown in FIG. 3, the optical transceivers using optical link B-C are optical transceiver 110-1 and optical transceiver 110-3. As mentioned above, optical transceiver 110-1 and optical transceiver 110-3 have not been diagnosed as abnormal (step S001 in FIG. 2: NO), so the abnormality location estimation unit 23 does not set an abnormality occurrence flag for optical link B-C.

Also, as shown in Figure 3, the optical transceiver using optical link C-D is optical transceiver 110-3. Because optical transceiver 110-3 has not been diagnosed as abnormal (step S001: NO in Figure 2), the abnormality location estimation unit 23 does not set an abnormality occurrence flag for optical link C-D.

Next, the abnormality location estimation unit 23 determines whether an abnormality occurrence flag has been set for all optical links through which the optical transceiver 110-2, which has been diagnosed as abnormal by the signal status diagnosis unit 22, passes (step S003 in Figure 2).

As shown in FIG. 3, the only optical link through which optical transceiver 110-2 passes is optical link A-B. As mentioned above, an abnormality occurrence flag has not been set for optical link A-B. In this case (step S003 in FIG. 2: YES), the abnormality occurrence location estimation unit 23 sets an abnormality occurrence flag for optical transceiver 110-2 (step S005 in FIG. 2).

Therefore, in the network configuration shown in FIG. 3, in a pattern in which an abnormality occurs in optical transceiver 110-2, an abnormality occurrence flag is set only for optical transceiver 110-2. In other words, if an abnormality occurs in optical transceiver 110-2, the abnormality occurrence location estimation unit 23 can correctly estimate that an abnormality has occurred in optical transceiver 110-2.

Finally, consider the sixth pattern, where an abnormality occurs in optical transceiver 110-3, for example. In this case, as described above, an abnormality is detected only in optical transceiver 110-3. The abnormality location estimation unit 23 of the optical network state estimation device 20 determines whether all optical transceivers using the optical links A-B, B-C, and C-D have been diagnosed as abnormal (step S001 in Figure 2).

As shown in Figure 3, the optical transceivers using optical link A-B are optical transceiver 110-1 and optical transceiver 110-2. As mentioned above, optical transceiver 110-1 and optical transceiver 110-2 have not been diagnosed as abnormal (step S001: NO in Figure 2), so the abnormality location estimation unit 23 does not set an abnormality occurrence flag for optical link A-B.

Also, as shown in Figure 3, the optical transceivers using optical link B-C are optical transceiver 110-1 and optical transceiver 110-3. As mentioned above, optical transceiver 110-3 has been diagnosed as abnormal, but optical transceiver 110-1 has not been diagnosed as abnormal (step S001: NO in Figure 2), so the abnormality location estimation unit 23 does not set an abnormality occurrence flag for optical link B-C.

Also, as shown in Figure 3, the only optical transceiver using optical link C-D is optical transceiver 110-3. Because optical transceiver 110-3 has been diagnosed as abnormal (step S001 in Figure 2: YES), the abnormality location estimation unit 23 sets an abnormality occurrence flag for optical link C-D (step S002 in Figure 2).

Next, the abnormality location estimation unit 23 determines whether an abnormality occurrence flag has been set for all optical links through which the optical transceiver 110-3, which has been diagnosed as abnormal by the signal status diagnosis unit 22, passes (step S003 in Figure 2).

As shown in FIG. 3, the optical links through which optical transceiver 110-3 passes are optical link B-C and optical link C-D. As mentioned above, an abnormality occurrence flag is not set for optical link B-C, but an abnormality occurrence flag is set for optical link C-D (step S003 in FIG. 2: NO). In this case, the abnormality occurrence location estimation unit 23 determines whether optical link C-D, for which an abnormality occurrence flag is set, is an optical link used only by optical transceiver 110-3 (and not used by other optical transceivers) (step S004 in FIG. 2).

Since optical link C-D is being used only by optical transceiver 110-3 (step S004 in Figure 2, YES), the anomaly occurrence location estimation unit 23 sets an anomaly occurrence flag for optical transceiver 110-3 (step S005 in Figure 2).

Therefore, in the network configuration shown in FIG. 3, in a pattern in which an abnormality occurs in optical transceiver 110-3, an abnormality occurrence flag is set for optical link C-D and optical transceiver 110-3. In other words, if an abnormality occurs in optical transceiver 110-3, the abnormality occurrence location estimation unit 23 cannot uniquely estimate the location of the abnormality, but it can narrow down the location of the abnormality by assuming that an abnormality has occurred in either optical link C-D or optical transceiver 110-3.

The results of setting the abnormality flag for each of the six abnormality location patterns described above are shown in Figure 4. As shown in Figure 4, except when the abnormality location is optical link B-C or optical transceiver 110-3, the abnormality location estimation unit 23 can uniquely and correctly estimate the abnormality location. Furthermore, even when the abnormality location is optical link B-C or optical transceiver 110-3, the abnormality location estimation unit 23 cannot determine whether the abnormality location is optical link B-C or optical transceiver 110-3, but it can narrow down the candidate abnormality locations to those two locations.

As described above, the optical network system 1 in the first embodiment can determine the location of an abnormality that has occurred in the optical network. In the maintenance and operation of an optical network, it is important to quickly detect abnormalities that are a sign of a failure and identify the location of the abnormality before a communication interruption occurs. The optical network system 1 in this embodiment is characterized by having a transmission signal information collection unit 21 that collects transmission signal information for the transmission section acquired by the optical transceiver 110 from multiple optical node devices 10 that make up the optical network, a signal status diagnosis unit 22 that diagnoses the normality of the transmission section based on the transmission signal information, and an abnormality location estimation unit 23 that estimates the location of the abnormality from multiple diagnosis results by the signal status diagnosis unit 22.

With this configuration, the optical network system 1 of this embodiment makes it possible to estimate the optical link section and transmitter/receiver where degradation in transmission quality has occurred based on transmission signal information obtained by multiple optical transceivers 110. As a result, the optical network system 1 of this embodiment can achieve efficient operation and maintenance of the optical network by quickly identifying the location of the abnormality.

(First Modification of the First Embodiment)
A first modified example of the first embodiment of the present invention will now be described. In the optical network system 1 in the first embodiment described above, the optical network state estimation device 20 is configured to include a signal state diagnosis unit 22. However, the present invention is not limited to this configuration, and for example, each optical node device may be configured to include a signal state diagnosis unit.

[Configuration of optical network system]
The configuration of an optical network system according to a first modification of the first embodiment will be described below. Fig. 5 is a diagram showing the overall configuration of an optical network system 1b according to a first modification of the first embodiment of the present invention. In the overall configuration diagram of Fig. 5, functional units having the same functions as those of the optical network system 1 according to the first embodiment described above are denoted by the same reference numerals, and a description of the functions may be omitted.

As shown in FIG. 5, the optical network system 1b in this modified example is configured to include four optical node devices 10b and an optical network state estimation device 20b. Note that in this modified example, as an example, the number of optical node devices 10b included in the optical network system 1b is four, but this is not limited to this and any number may be used.

As shown in FIG. 5, the optical node device 10b includes an optical signal input/output unit 11, an optical cross-connect unit 12, and a signal status diagnosis unit 13.

The optical signal input/output unit 11 inputs and outputs signals transmitted over the optical links connecting the optical node devices 10. The optical signal input/output unit 11 is equipped with optical transceivers 110 (Tx/Rx) that transmit client signals depending on the actual communication situation. The optical signal input/output unit 11 outputs transmission signal information for the transmission section acquired by the optical transceiver 110 to the signal status diagnosis unit 13.

The signal state diagnostic unit 13 acquires the transmission signal information output from the optical signal input/output unit 11. The signal state diagnostic unit 13 diagnoses the normality of the transmission section based on the acquired transmission signal information (detects whether an abnormality has occurred). Specifically, the signal state diagnostic unit 13 determines whether the transmission section passing through each optical transceiver 110 is normal (whether an abnormality has occurred). For example, the signal state diagnostic unit 13 determines that an abnormality has occurred when the received power value or bit error rate value falls below a predetermined threshold. The signal state diagnostic unit 13 transmits information indicating the diagnosis result of the normality of the transmission section (the abnormality detection result) to the optical network state estimation device 20b.

The signal condition diagnosis unit 13 may be configured to perform machine learning using a neural network or the like using, for example, a digitally modulated signal, and then use the trained neural network or the like to determine whether or not an abnormality has occurred in the transmission section.

As shown in FIG. 5, the optical network status estimation device 20 includes a transmission signal information collection unit 21b and an abnormality location estimation unit 23. The transmission signal information collection unit 21b receives information indicating the diagnosis results of the normality of the transmission section (the abnormality detection results) from each optical node device 10b in the monitored section of the optical network. The transmission signal information collection unit 21b outputs the received information indicating the diagnosis results of the normality of the transmission section (the abnormality detection results) to the signal status diagnosis unit 22.

The abnormality location estimation unit 23 acquires information indicating the diagnosis results for the normality of the transmission section, output from the transmission signal information collection unit 21b. The abnormality location estimation unit 23 estimates the abnormality location based on the acquired information. Note that the abnormality location in this embodiment refers to the optical link in which the abnormality has occurred and the optical transceiver 110 in which the abnormality has occurred.

(Second Modification of the First Embodiment)
A second modified example of the first embodiment of the present invention will be described below. In the optical network system 1 in the first embodiment described above, a single-mode optical fiber 30 is used for the optical link connecting the optical node devices 10, and wavelength multiplexing communication is performed by the wavelength multiplexing unit 15. However, the present invention is not limited to this configuration, and for example, any medium may be used for the optical link connecting the optical node devices.

In the second variant of the first embodiment described below, a multi-core optical fiber 30c is used for the optical link connecting the optical node devices 10c, and spatial multiplexing communication is performed using fan-in/fan-out 15c.

[Configuration of optical network system]
The configuration of an optical network system according to a second modification of the first embodiment will be described below. Fig. 6 is a diagram showing the overall configuration of an optical network system 1c according to the second modification of the first embodiment of the present invention. In the overall configuration diagram of Fig. 6, functional units having the same functions as those of the functional units included in the optical network system 1 according to the first embodiment described above are given the same reference numerals, and descriptions of those functions may be omitted.

As shown in FIG. 6, the optical network system 1c in this modified example is configured to include four optical node devices 10c and an optical network state estimation device 20. In this modified example, as an example, the optical network system 1c has four optical node devices 10c, but this is not limited to this and any number may be used.

As shown in FIG. 6, the optical node device 10c includes an optical signal input/output unit 11 and an optical cross-connect unit 12c.

The optical signal input/output unit 11 inputs and outputs signals transmitted over the optical links connecting the optical node devices 10c. The optical signal input/output unit 11 is equipped with optical transceivers (Tx/Rx) that transmit client signals depending on the actual communication situation. As shown in Figure 6, this variant assumes that optical transceivers 110-1 to 110-3 are provided.

The optical cross-connect unit 12c determines the input and output paths of optical signals. The optical cross-connect unit 12c includes a fan-in/fan-out 15c. A multi-core optical fiber 30c is used for the optical links connecting the optical node devices 10c. The fan-in/fan-out 15c accommodates the optical transceivers 110-1 to 110-3 in any of the cores. This allows spatial multiplexing communication to be performed.

Figure 7 is a cross-sectional view of a multi-core optical fiber 30c of an optical network system 1c in a second modified example of the first embodiment of the present invention. For example, as shown in Figure 7, spatial multiplexing communication is performed by accommodating optical transceiver (Tx/Rx) 110-1 in one core and optical transceiver 110-2 and optical transceiver 110-3 in the other core.

In this way, even in optical network system 1c, which uses multi-core optical fibers in the optical links connecting optical node devices and is configured to perform spatial multiplexing communication, it is possible to estimate the location of an abnormality in the optical network (the optical link or optical transceiver where the abnormality occurred), just as in the optical network system 1 in the first embodiment described above, which performs wavelength multiplexing communication.

Second Embodiment
The second embodiment of the present invention will be described below with reference to the drawings. The optical network system 1 in the first embodiment described above is configured to determine the location of an abnormality in the optical network by using a function that is pre-installed in the optical transceiver 110 to measure signal quality, such as the value of received power or the value of bit error rate.

In contrast, the optical network system in the second embodiment described below combines the above functions with an OTDR to more accurately determine the location of an abnormality in the optical network. While an OTDR cannot detect abnormalities in optical transceivers, it can evaluate optical fiber loss by observing the reflected light (backscattered light) of optical pulses sent to the optical fiber. This allows the OTDR to more accurately estimate the location of an abnormality in the optical link.

[Configuration of optical network system]
9, in an optical network system 1d in this embodiment, an optical node device 10A is provided with an OTDR 111. The OTDR 111 transmits an OTDR signal from the optical node device 10A to an optical node device 10D via an optical node device 10B and an optical node device C. In the optical node device 10D, the termination point of the OTDR signal is open.

[Operation of Optical Network State Estimation Device]
An example of the operation of the optical network status estimating device 20d according to this embodiment will be described below with reference to Figures 8 to 10. In this embodiment, it is assumed that the configuration of the optical network, the connection status of each optical transceiver, and the diagnosis result of the normality of each optical transceiver by the signal status diagnostic unit 22 are known.

In this embodiment, as with the first embodiment described above, it is assumed that an abnormality occurs in only one location in the optical network, and that abnormalities do not occur in multiple locations at the same time. Specifically, in this embodiment, it is assumed that an abnormality occurs in the optical network in one of the optical links or one of the optical transceivers.

Figure 8 is a flowchart showing the operation of the optical network state estimation device 20d in the second embodiment of the present invention. Figure 9 is a diagram showing an example of an optical network configuration to explain the operation of the optical network state estimation device 20d. Figure 10 is a diagram showing abnormality occurrence patterns and normality diagnosis results in the optical network shown in Figure 9.

The operation of the optical network state estimation device 20d shown in the flowchart of Figure 8 is initiated, for example, when transmission loss information is transmitted from the OTDR 111 to the optical network state estimation device 20d. The transmission loss information is information that indicates the loss of optical fibers in the optical network, measured by the OTDR 111.

First, the anomaly location estimation unit 23d of the optical network state estimation device 20d acquires transmission loss information output from the OTDR 111 of the optical node device 10A (step S101). This determines whether an anomaly has occurred in all optical links from the optical node device 10A to the optical node device 10D.

If the transmission loss information includes information about an abnormality (step S102, YES), the abnormality location estimation unit 23d sets an abnormality flag for the optical link in which it is determined that an abnormality has occurred (step S103).

Next, for each optical transceiver diagnosed as abnormal by the signal condition diagnosis unit 22, the abnormality occurrence location estimation unit 23d determines whether an abnormality occurrence flag has been set (by the processing of step S103 above) in all optical links through which the optical transceiver passes (step S104). In other words, the abnormality occurrence location estimation unit 23d determines whether an abnormality occurrence flag has been set (by the processing of step S103 above) in at least one optical link through which the optical transceiver passes.

If an abnormality occurrence flag has not been set for all optical links through which the optical transceiver passes (step S104: YES), the abnormality occurrence location estimation unit 23d performs a process to set an abnormality occurrence flag for the optical transceiver 110 in question (step S105).

When the abnormality location estimation unit 23d has repeated the processing from step S104 onwards for all optical transceivers diagnosed as abnormal by the signal state diagnosis unit 22, the operation of the optical network state estimation device 20d shown in the flowchart of Figure 8 ends.

Below, we will explain a specific example of when the processing of the flowchart shown in Figure 8 above is performed, with reference to Figures 9 and 10.

Figure 9 shows the overall configuration of the optical network system 1d and the configuration of the optical network in the specific example described below. As shown in Figure 8, the optical network system 1d in the specific example described below is configured to include an optical node device 10A, an optical node device 10B, an optical node device 10C, an optical node device 10D, and an optical network state estimation device 20d.

Optical node device 10A, optical node device 10B, optical node device 10C, and optical node device 10D are communicatively connected to one another via optical links using single-mode optical fibers 30, forming an optical network. Optical node device 10A, optical node device 10B, optical node device 10C, and optical node device 10D each include an optical signal input/output unit 11 and an optical cross-connect unit 12. Furthermore, optical cross-connect unit 12 includes a wavelength multiplexing unit 15.

Furthermore, only the optical node device 10A is equipped with an OTDR 111. The OTDR 111 transmits an OTDR signal from the optical node device 10A to the optical node device 10D via the optical node device 10B and the optical node device C. The OTDR 111 also transmits transmission loss information indicating the loss of the optical fiber in the optical network, measured by transmitting the OTDR signal, to the optical network state estimation device 20d.

Hereinafter, the optical link connecting optical node device 10A and optical node device 10B will be referred to as "optical link A-B," the optical link connecting optical node device 10B and optical node device 10C will be referred to as "optical link B-C," and the optical link connecting optical node device 10C and optical node device 10D will be referred to as "optical link C-D."

The optical signal input/output unit 11 is equipped with optical transceivers (Tx/Rx) that transmit client signals depending on the actual communication situation. In the specific example described below, as shown in FIG. 9, it is assumed that optical transceiver 110-1 is provided between optical node device 10A and optical node device 10C, optical transceiver 110-2 is provided between optical node device 10A and optical node device 10B, and optical transceiver 110-3 is provided between optical node device 10B and optical node device 10D.

As shown in Figure 9, the optical links that optical transceiver 110-1 passes through are optical link A-B and optical link B-C, the optical link that optical transceiver 110-2 passes through is only optical link A-B, and the optical links that optical transceiver 110-3 passes through are optical link B-C and optical link C-D. With the above configuration, wavelength-multiplexed communications are performed between optical node device 10A and optical node device 10C, between optical node device 10A and optical node device 10B, and between optical node device 10B and optical node device 10D by optical transceivers 110-1, 110-2, and 110-3, respectively.

The optical network state estimation device 20d evaluates the communication state of an optical network composed of optical node devices 10A, 10B, 10C, and 10D. As shown in FIG. 9, the optical network state estimation device 20d includes a transmission signal information collection unit 21, a signal state diagnosis unit 22, and an abnormality location estimation unit 23d.

As mentioned above, in this embodiment, when an abnormality occurs in the optical network, it is assumed that the abnormality occurs in one location and that abnormalities do not occur in multiple locations at the same time. Therefore, in this specific example, the location where the abnormality occurs in the optical network is either one of optical link A-B, optical link B-C, or optical link C-D, or one of optical transceiver 110-1, optical transceiver 110-2, or optical transceiver 110-3. In other words, there are six possible locations where an abnormality can occur in the optical network of this specific example.

Note that abnormalities occurring in optical links A-B, B-C, and C-D are, for example, communication failures caused by bending of the optical fiber. Furthermore, abnormalities occurring in optical transceivers 110-1, 110-2, and 110-3 are, for example, malfunctions in the optical transceivers themselves.

Figure 10 shows six possible patterns of abnormality locations that can occur in the optical network of Figure 9, and the correspondence between each pattern and the optical transceiver in which the signal status diagnosis unit 22 detects an abnormality when an abnormality occurs at each abnormality location.

As shown in FIG. 10, if the abnormality occurs in optical link A-B, the abnormality is detected in optical transceivers 110-1 and 110-2, which are optical transceivers (Tx/Rx) passing through optical link A-B. If the abnormality occurs in optical link B-C, the abnormality is detected in optical transceivers 110-1 and 110-3, which are optical transceivers passing through optical link B-C. If the abnormality occurs in optical link C-D, the abnormality is detected in optical transceiver 110-3, which is an optical transceiver passing through optical link C-D.

Furthermore, as shown in FIG. 10, if the abnormality occurs in optical transceiver 110-1, the abnormality is detected in optical transceiver 110-1; if the abnormality occurs in optical transceiver 110-2, the abnormality is detected in optical transceiver 110-2; and if the abnormality occurs in optical transceiver 110-3, the abnormality is detected in optical transceiver 110-3. Based on the correspondence between the abnormality occurrence locations and the optical transceivers in which the abnormality is detected, it is possible to narrow down or identify the abnormality location from the optical transceiver in which the abnormality is detected.

[Example of setting an error flag]
Hereinafter, a flow up to the setting of an abnormality occurrence flag by the operation of the optical network state estimating device 20d shown in FIG. 8 will be described for each of six patterns of abnormality occurrence locations that can occur in the optical network of FIG.

First, consider the first pattern, where an abnormality occurs in optical link A-B due to, for example, bending of the optical fiber. In this case, OTDR 111 detects an abnormality in optical link A-B (steps S101 and S102 in FIG. 8). The abnormality occurrence location estimation unit 23d sets an abnormality occurrence flag for optical link A-B (step S103 in FIG. 8). Thus, in the network configuration shown in FIG. 9, in a pattern where an abnormality occurs in optical link A-B, an abnormality occurrence flag is set only for optical link A-B. In other words, if an abnormality occurs in optical link A-B, the abnormality occurrence location estimation unit 23d can correctly estimate that an abnormality has occurred in optical link A-B.

Figure 10 shows six possible patterns of abnormality locations that can occur in the optical network of Figure 9, along with the corresponding abnormality flags that are set when an abnormality occurs at each abnormality location.

Next, consider the second pattern, where an abnormality occurs in optical link B-C due to, for example, bending of the optical fiber. In this case, the OTDR 111 detects an abnormality in optical link B-C (steps S101 and S102 in FIG. 8). The abnormality occurrence location estimation unit 23d sets an abnormality occurrence flag for optical link B-C (step S103 in FIG. 8). Thus, in the network configuration shown in FIG. 9, in a pattern where an abnormality occurs in optical link B-C, an abnormality occurrence flag is set only for optical link B-C. In other words, if an abnormality occurs in optical link B-C, the abnormality occurrence location estimation unit 23d can correctly estimate that an abnormality has occurred in optical link B-C.

Next, consider the third pattern, where an abnormality occurs in optical link C-D due to, for example, bending of the optical fiber. In this case, the OTDR 111 detects an abnormality in optical link C-D (steps S101 and S102 in FIG. 8). The abnormality location estimation unit 23d sets an abnormality occurrence flag for optical link C-D (step S103 in FIG. 8). Thus, in the network configuration shown in FIG. 9, in a pattern where an abnormality occurs in optical link C-D, an abnormality occurrence flag is set only for optical link C-D. In other words, if an abnormality occurs in optical link B-C, the abnormality location estimation unit 23d can correctly estimate that an abnormality has occurred in optical link C-D.

Next, consider the fourth pattern, where an abnormality occurs in optical transceiver 110-1, for example. In this case, as mentioned above, an abnormality is detected only in optical transceiver 110-1. Furthermore, in this case, OTDR 111 does not detect an abnormality in any of the optical links (step S102 in Figure 8: NO).

Next, the abnormality location estimation unit 23d determines whether an abnormality occurrence flag has been set for all optical links through which the optical transceiver 110-1 diagnosed as abnormal by the signal status diagnosis unit 22 passes (step S104 in Figure 8).

As shown in FIG. 9, the optical links through which the optical transceiver 110-1 passes are optical link A-B and optical link B-C. As mentioned above, no abnormality flags have been set for optical link A-B or optical link B-C. In this case (step S104 in FIG. 8: YES), the abnormality location estimation unit 23 sets an abnormality flag for the optical transceiver 110-1 (step S105 in FIG. 8).

Therefore, in the network configuration shown in FIG. 9, in a pattern in which an abnormality occurs in optical transceiver 110-1, an abnormality occurrence flag is set only for optical transceiver 110-1. In other words, if an abnormality occurs in optical transceiver 110-1, the abnormality occurrence location estimation unit 23d can correctly estimate that an abnormality has occurred in optical transceiver 110-1.

Next, consider the fifth pattern, where an abnormality occurs in optical transceiver 110-2, for example. In this case, as mentioned above, an abnormality is detected only in optical transceiver 110-2. Also, in this case, OTDR 111 does not detect an abnormality in any of the optical links (step S102 in Figure 8: NO).

Next, the abnormality location estimation unit 23d determines whether an abnormality occurrence flag is set for all optical links through which the optical transceiver 110-2, which has been diagnosed as abnormal by the signal status diagnosis unit 22, passes (step S104 in Figure 8).

As shown in FIG. 9, the only optical link through which the optical transceiver 110-2 passes is optical link A-B. As mentioned above, an abnormality occurrence flag has not been set for optical link A-B. In this case (step S104 in FIG. 8: YES), the abnormality occurrence location estimation unit 23 sets an abnormality occurrence flag for the optical transceiver 110-2 (step S105 in FIG. 8).

Therefore, in the network configuration shown in FIG. 9, in a pattern in which an abnormality occurs in the optical transceiver 110-2, an abnormality occurrence flag is set only for the optical transceiver 110-2. In other words, if an abnormality occurs in the optical transceiver 110-2, the abnormality occurrence location estimation unit 23d can correctly estimate that the abnormality has occurred in the optical transceiver 110-2.

Finally, consider the sixth pattern, where an abnormality occurs in optical transceiver 110-3, for example. In this case, as mentioned above, an abnormality is detected only in optical transceiver 110-3. Furthermore, in this case, OTDR 111 does not detect an abnormality in any of the optical links (step S102 in Figure 8: NO).

Next, the abnormality location estimation unit 23d determines whether an abnormality occurrence flag is set for all optical links through which the optical transceiver 110-3, which has been diagnosed as abnormal by the signal status diagnosis unit 22, passes (step S104 in Figure 8).

As shown in FIG. 9, the optical links through which the optical transceiver 110-3 passes are optical link B-C and optical link C-D. As mentioned above, no abnormality flags have been set for optical link B-C and optical link C-D. In this case (step S104 in FIG. 8: YES), the abnormality location estimation unit 23 sets an abnormality flag for the optical transceiver 110-3 (step S105 in FIG. 8).

Therefore, in the network configuration shown in FIG. 9, in a pattern in which an abnormality occurs in the optical transceiver 110-3, an abnormality occurrence flag is set only for the optical transceiver 110-3. In other words, if an abnormality occurs in the optical transceiver 110-3, the abnormality occurrence location estimation unit 23d can correctly estimate that the abnormality has occurred in the optical transceiver 110-3.

The results of setting the abnormality flag for each of the six patterns of abnormality locations described above are shown in Figure 10. As shown in Figure 10, in this embodiment, unlike the first embodiment described above, the abnormality location estimation unit 23d can uniquely and correctly estimate the abnormality location for any of the six patterns of abnormality locations described above. This is because, unlike the first embodiment described above, in this embodiment, optical link abnormalities can be identified by the OTDR 111, making it possible to determine whether the abnormality is in the optical link or the optical transceiver.

(Modification of the second embodiment)
The optical network system 1d in the second embodiment described above is configured to first determine whether or not an abnormality has occurred in the optical link based on the transmission loss information acquired from the OTDR 111. If an abnormality is detected in the optical link, the optical network system 1d then identifies the optical link where the abnormality has occurred, and if no abnormality is detected in the optical link, the optical network system 1d is configured to identify the optical transceiver where the abnormality has occurred based on the transmission signal information.

In contrast, the optical network system in this modified example of the second embodiment first performs the same operations as the optical network system 1 in the first embodiment, as shown in the flowchart in Figure 2 above. Then, if the optical network system in this modified example is unable to determine whether the abnormality is in the optical link or the optical transceiver, it uses an OTDR to identify whether an abnormality has occurred in the optical link. This allows the optical network system in this modified example to determine whether the abnormality is in the optical link or the optical transceiver.

Note that a case in which it is not possible to determine whether the abnormality is in the optical link or the optical transceiver is, for example, a case in the first embodiment described above in which it is not possible to determine whether the abnormality is in the optical link C-D or the optical transceiver 110-3 shown in FIG. 4.

Note that the configuration of the optical network system in this modified example is similar to the configuration of the optical network system 1d in the second embodiment shown in Figure 9 above, and therefore a detailed description will be omitted.

[Operation of Optical Network State Estimation Device]
An example of the operation of the optical network state estimating device in this modification will be described below with reference to Fig. 11. In this modification, it is assumed that the configuration of the optical network, the connection status of each optical transceiver 110, and the normality diagnosis results of each optical transceiver 110 by the signal state diagnostic unit 22 are known.

Figure 11 is a flowchart showing the operation of an optical network state estimation device in a modified example of the second embodiment of the present invention. The operation of the optical network state estimation device shown in the flowchart of Figure 11 is initiated, for example, when the signal state diagnosis unit 22 diagnoses that at least one of the optical transceivers 110 is abnormal.

Note that the operation of the optical network state estimation device from step S201 to step S205 in the flowchart shown in FIG. 11 is similar to the operation of the optical network state estimation device 20 in the first embodiment from step S001 to step S005 in the flowchart shown in FIG. 2 described above, and therefore will not be described again.

If multiple abnormality flags are set, the abnormality location estimation unit 23d acquires the transmission loss information output from the OTDR 111. Based on the acquired transmission loss information, the abnormality location estimation unit 23d determines whether or not an abnormality has occurred in the optical link for which the abnormality flag is set (step S206).

If the abnormality location estimation unit 23d determines that an abnormality has occurred in an optical link for which an abnormality flag has been set, it deletes the abnormality flag set in the optical transceiver. Furthermore, if the abnormality location estimation unit 23d determines that no abnormality has occurred in an optical link for which an abnormality flag has been set, it deletes the abnormality flag set in that optical link. This completes the operation of the optical network state estimation device shown in the flowchart of Figure 11.

As described above, in the optical network system of this modified example, unlike the first embodiment described above, the anomaly occurrence location estimation unit 23d can uniquely and correctly estimate the location of the anomaly. This is because, unlike the first embodiment described above, in this embodiment, an optical link anomaly can be identified by the OTDR 111, making it possible to determine whether the anomaly is in the optical link or in the optical transceiver.

According to the above-described embodiment, the abnormality location determination device includes a collection unit, a diagnosis unit, and a determination unit. For example, the abnormality location determination device is the optical network status estimation device 20, 20b, or 20d in the embodiment, the collection unit is the transmission signal information collection unit 21 or 21b in the embodiment, the diagnosis unit is the signal status diagnosis unit 13 or 22 in the embodiment, and the determination unit is the abnormality location estimation unit 23 or 23d in the embodiment.

The collection unit collects transmission signal information for the transmission section obtained by the optical transceiver from multiple optical nodes that make up the optical network. The diagnosis unit diagnoses the normality of the transmission section based on the transmission signal information. The determination unit determines the location of an abnormality in the optical network based on the results of multiple diagnoses by the diagnosis unit. For example, the optical node is the optical node device 10, 10b in the embodiment, the optical transceiver is the optical transceiver 110 in the embodiment, the transmission section is the optical link in the embodiment, and the abnormal location is the location where the abnormality occurred in the embodiment.

The anomaly location determination device may further include an optical pulse tester. In this case, the optical pulse tester determines whether an anomaly has occurred in the optical link between optical nodes and generates optical link status information indicating the determination result. If the determination unit cannot identify whether the anomaly is in the optical link or the optical transceiver based on the results of the above diagnosis, it identifies it based on the optical link status information. For example, the optical pulse tester is the OTDR 111 in the embodiment, and the optical link status information is transmission loss information in the embodiment.

The determination unit may determine whether an abnormality has occurred in the optical link based on the optical link status information, and then determine the location of the abnormality based on the results of the above determination for each optical link and the results of the above diagnosis.

The determination unit may also extract optical links and optical transceivers that are candidates for the abnormal location based on the results of the above diagnosis, and identify whether the abnormal location is the optical link or the optical transceiver based on the optical link status information.

The diagnostic unit may be provided in each of multiple optical nodes.

The transmission signal information may include the digitally modulated signal received by the optical transceiver, the received power value, or the bit error rate value.

The optical network state estimation device and optical node device in the above-described embodiments may be implemented in part or in whole by a computer. In this case, a program for implementing this function may be recorded on a computer-readable recording medium, and the program may be loaded and executed by a computer system. Note that the term "computer system" as used herein includes the operating system and peripheral hardware. Furthermore, "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into computer systems. Furthermore, "computer-readable recording medium" may also include media that dynamically store programs for a short period of time, such as communication lines used when transmitting programs over networks such as the Internet or over communication lines such as telephone lines, or media that store programs for a fixed period of time, such as volatile memory within the computer system that serves as the server or client. The program may be designed to implement some of the above-described functions, or may be capable of implementing the above-described functions in combination with a program already stored in the computer system, or may be implemented using a programmable logic device such as an FPGA (Field Programmable Gate Array).

The above describes in detail an embodiment of the present invention with reference to the drawings, but the specific configuration is not limited to this embodiment and includes designs that do not deviate from the gist of the present invention.

1, 1a, 1b, 1c, 1d... Optical network system, 10, 10b... Optical node device, 11... Optical signal input/output unit, 12, 12c... Optical cross-connect unit, 13... Signal status diagnosis unit, 15... Wavelength multiplexing unit, 15c... Fan-in/fan-out, 20, 20b, 20d... Optical network status estimation device, 21, 21b... Transmission signal information collection unit, 22... Signal status diagnosis unit, 23, 23d... Abnormality location estimation unit, 30... Single-mode optical fiber, 30c... Multi-core optical fiber, 110... Optical transceiver

Claims (8)

a collection unit that collects transmission signal information of a transmission section acquired by an optical transceiver from a plurality of optical nodes that constitute an optical network;
a diagnosis unit that diagnoses the normality of the transmission section based on the transmission signal information;
a determination unit that determines an abnormality location in the optical network based on a plurality of results of the diagnosis by the diagnosis unit;
Equipped with
The abnormality location determination device, wherein the determination unit determines that the optical link is the abnormal location if all the optical transceivers using the optical link in each of the transmission sections are diagnosed as abnormal, and determines that the optical transceiver is the abnormal location if all the optical links through which the optical transceiver diagnosed as abnormal passes are determined to be normal . a collection unit that collects transmission signal information of a transmission section acquired by an optical transceiver from a plurality of optical nodes that constitute an optical network;
a diagnosis unit that diagnoses the normality of the transmission section based on the transmission signal information;
a determination unit that determines an abnormality location in the optical network based on a plurality of results of the diagnosis by the diagnosis unit;
an optical time domain tester that determines whether an abnormality has occurred in the optical link between the optical nodes and generates optical link status information indicating the determination result ;
Equipped with
When the determination unit cannot determine whether the abnormal part is in the optical link or the optical transceiver based on the result of the diagnosis, the determination unit determines whether the abnormal part is in the optical link or the optical transceiver based on the optical link status information.
An abnormality location determination device. 3. The abnormality location determination device according to claim 2, wherein the determination unit determines whether or not an abnormality has occurred in the optical link based on the optical link status information, and then determines the abnormal location based on the result of the determination for each optical link and the result of the diagnosis. 3. The abnormality location determination device according to claim 2, wherein the determination unit extracts optical links and optical transceivers that are candidates for the abnormal location based on the results of the diagnosis, and identifies whether the abnormal location is the optical link or the optical transceiver based on the optical link status information. The abnormality occurrence location determination device according to claim 1 , wherein the diagnostic unit is provided in each of the plurality of optical nodes. The abnormality location determining device according to claim 1 , wherein the transmission signal information includes a digitally modulated signal received by the optical transceiver, a received power value, or a bit error rate value. a collecting step of collecting transmission signal information of a transmission section acquired by an optical transceiver from a plurality of optical nodes constituting the optical network;
a diagnosis step of diagnosing the normality of the transmission section based on the transmission signal information;
an estimation step of estimating an abnormality location in the optical network based on a plurality of results of the diagnosis in the diagnosis step;
and
In the estimation step, for each optical link in the transmission section, if all the optical transceivers using the optical link are diagnosed as abnormal, the optical link is determined to be the abnormal location, and if all the optical links through which the optical transceiver diagnosed as abnormal passes are determined to be normal, the optical transceiver is determined to be the abnormal location. A program for causing a computer to function as the abnormality location determination device described in any one of claims 1 to 6.